Figure 3

The superimposition of the catalytic triad TKH in the two structures [UOX/UA/CN] and [UOX/8-AZA] crystallized in cyanide. This shows how the cyanide present in the first structure influences the H-bond network (black dotted lines for cyanide/uric acid and pink dotted lines for 8-AZA complexes). The permanent negative charge of the cyanide induces a drastic change in the H-bond network continuity with a nearly broken Thr 57* – Lys 10* connection (3.51 Å compared to 2.86 Å in the non-cyanide 8-AZA complex). A similar discontinuity is observed when a chloride anion is located in the oxygen/W1 hole [10].